Effect of lactoferrin supplementation combined with standard therapy on Helicobacter pylori infection in children　WANG Yanli¹, LI Chunli², ZHUANG Tanyue², CHENG Yanbo¹ (1. Department of Pediatrics, The First People's Hospital of Zhengzhou, Zhengzhou 450003, henan, China; 2. Department of Pediatrics, The People's Hospital of Zhengzhou, Zhengzhou 450053, Henan, China)